a. Field of the Invention
The instant invention relates to ablation electrodes and/or electrode assemblies. The present invention further relates to ablation electrodes and/or assemblies having a mechanism for irrigating targeted areas. The present invention further relates to irrigated ablation electrodes and/or assemblies that allow for a parallel irrigation flow path through the use of polygonal shaped electrodes.
b. Background Art
Electrophysiology catheters have been used for an ever-growing number of procedures. For example, catheters have been used for diagnostic, therapeutic, and ablative procedures, to name just a few examples. Typically, a catheter is manipulated through the patient's vasculature and to the intended site, for example, a site within the patient's heart, and carries one or more electrodes, which may be used for ablation, diagnosis, or other treatments.
There are a number of methods used for ablation of desired areas, including for example, radiofrequency (RF) ablation. RF ablation is accomplished by transmission of radiofrequency energy to a desired target area through an electrode assembly to ablate tissue at the target site. Because RF ablation may generate significant heat, which if not controlled can result in excessive tissue damage, such as steam pop, tissue charring, and the like, it is desirable to include a mechanism to irrigate the target area and the device with biocompatible fluids, such as saline solution. The use of irrigated ablation catheters can also prevent the formation of soft thrombus and/or blood coagulation.
Typically, there are two classes of irrigated electrode catheters, open and closed irrigation catheters. Closed ablation catheters usually circulate a cooling fluid within the inner cavity of the electrode. Open ablation catheters typically deliver the cooling fluid through open outlets or openings on the surface of the electrode. Open ablation catheters use the inner cavity of the electrode, or distal member, as a manifold to distribute saline solution, or other irrigation fluids known to those skilled in the art, to one or more passageways that lead to openings/outlets provided on the surface of the electrode. The saline thus flows directly through the outlets of the passageways onto the distal electrode member. This direct flow of fluid through the electrode tip lowers the temperature of the tip during operation, rendering accurate monitoring and control of the ablative process more difficult. Accordingly, it is desirable to have a method that allows for cooling of the electrode while having accurate monitoring and control of the ablative process.
The irrigation of electrodes, especially those of longer length (i.e., for example, over 3 mm), have an increased likelihood of developing thrombus caused by protein aggregation and blood coagulation, due to angled irrigation flow away from the electrode tip. Moreover, as the length of the electrode increases, the angled fluid passageways provided by an electrode assembly, are less effective since the fluid is directed away from the electrode instead of along the body of the electrode to effectively cool the electrode and adequately irrigate in order to prevent the development of thrombus. Overall, open flush irrigated ablation catheters may improve the safety of RF catheter ablation by preventing protein aggregation and blood coagulation.